The correct option is B 14x2+12xy+8y2−4x
Given the adjacent sides of the rectangle are
6x2+4y2+2xy and x2−2x+4xy
The perimeter of the rectangle = 2(length + breadth)
So, the perimeter
=2[(6x2+4y2+2xy)+(x2−2x+4xy)]
=2(7x2+6xy+4y2−2x)
=14x2+12xy+8y2−4x
Hence, the perimeter of the rectangle
=14x2+12xy+8y2−4x